That capacity crunch has been driven by Twitter, which outsources its infrastructure to NTT America through a managed hosting agreement. Twitter experienced 752 percent traffic growth in 2008, but that was nothing compared to the traffic explosion in the first half of 2009, as the microblogging service went mainstream and was widely adopted by celebrities and a growing number of businesses.

NTT America Chief Operating Office Kazuhiro Gomi said in June that "traffic generated by Twitter is getting so big, it’s basically eating up a lot of our data center network resources, especially the segment where Twitter is hosted. Other customers are riding on the same segment" in the company's primary data center in San Jose, he said.

Twitter's consumption of NTT America's resources was an issue in the timing of a "critical network upgrade" in June, which was postponed when Twitter become a key communciations tool during the aftermath of elections in Iran. In a blog post at the time, Twitter's Biz Stone acknowledged the strain Twitter's growth was placing on NTT America's infrastructure. "Our partners are taking a huge risk not just for Twitter but also the other services they support worldwide," Stone wrote. "We commend them for being flexible in what is essentially an inflexible situation."

The new NTT America site in Santa Clara is equipped with redundant power feeds, fully redundant water cooling systems, advanced humidity and temperature controls and a multi-gigabit interconnection to NTT America’s Tier 1 Internet Backbone.

"The Silicon Valley technology corridor is an important market for customers who require enterprise-grade data center facilities for their corporate IT infrastructure," said Gomi. "Our data center expansion enables us to provide customers with a Tier III colocation facility and the flexibility to add managed services to meet current and changing needs. We are delighted to extend NTT America’s high standards of IT infrastructure, security and performance to customers in our new Santa Clara data center."

Twitter's infrastructure performance has been a topic of ongoing interest among its power users. After a miserable uptime performance in 2007, Twitter reworked its infrastructure, shifting to NTT America in early 2008. The service improved its performance, an effort that was reviewed by Twitter's John Adams at the Velocity 2009 conference. But there have been reliability stumbles in recent weeks, most notably an Aug. 6 denial of service attack that also slowed Facebook and LiveJournal.